Head restraint assemblies, which generally comprise a headrest component—commonly called a bun—adjustably supported on the top of a seat-back, protect a vehicle occupant from serious injury due to sudden acceleration or deceleration of the vehicle. In one typical form thereof, head restraints are adjustable relative to the seat-back both vertically as well as forwardly and rearwardly in order to permit their proper positioning for the occupant. Forward and rearward adjustment is typically accomplished with a ratchet-style mechanism which, upon occupant actuation of a release means (such as, for instance, a button or lever), releases the ratchet mechanism to permit the head restraint to move under spring bias to a full-forward position. From this position, the head restraint can be moved rearwardly into one of a plurality of intermediate positions, each defined by the ratchet mechanism. Because of this construction, it is possible for the ratchet mechanism to be inadvertently released, such as in the event of a rear impact, and moved forward to a position that may enhance the risk of occupant injury.